Accident- and tampering-proof attachment means of an object to a stationary support

Abstract

A shock-, vibrations- and tampering-proof attachment means of an object, h as a signal producing insert of an ionization alarm system coaxially and non-rotatably to a support, such as for land-, marine- and air vehicles provides a spring assembly with a spring and biased coaxial protrusion in the bottom of the object with a helically wound canal running through the protrusion having end orifices in its surface. The support is provided with a U-shaped fork fixed with its yoke in it. A connecting means equipped with a rod traverses the protrusion perpendicularly to its axis. The rod is fastened to both free ends of the yoke. Optimum shapes and dimensions of the respective parts are established, also with the view of maintaining a minimum size of the object itself. The object with the fixed protrusion is mounted by rotation thereof to the support, thus hiding the attachment means and making them vibration proof and inaccessible from the outside. An attempt to disassemble the attachment by re-rotation of the object relative to the support results only firstly in moving the point of engagement of the attachment upwardly toward the vertex of the canal, simultaneously distancing the protrusion from the spring assembly and subsequently reversing the axial motion of the protrusion toward the spring assembly with the point of engagement of the attachment continuing to move to the end of the canal or channel, thus preventing axial separation and a reverse rotation without excessive force.

What is claimed is: 
     
       1. A shock-, vibrations-, and tampering-proof attachment means of an object, such as a signal producing insert of an ionization alarm system coaxially along a common central axis to a fixed support face of a support, such as of land-, marine- and air-vehicles, A. said object comprising: A 1. an elongated protrusion mounted nonrotatably and coaxially in the bottom of said object and protruding through its bottom downwardly facing said support face;   A 2. a spring assembly mounted coaxially within the bottom of said object;   A 3. a helical crescent shaped channel with openings within the protruding bottom of said protrusion said channel continuing with a vertex directed upwardly and from there to its end;     B. said support provided with a connector means for a rod, said connector means fixed nonrotatably coaxially with said protrusion; said connector means protruding upwardly from said support;   C. a rod mounted between the said connector means and reaching into said protrusion to engage said channel in a direction substantially radial to the common axis to permit assembly of said object with said support by rotation of the former relative to the latter, to prevent their separation by accident or design;   said spring assembly comprising an axial helical spring and an upper stop, the protrusion being provided with a head, being mounted within said spring and pushed by it upwardly with the head against the stop away from the connecting element;   the axial distance of the path between the openings within the protruding bottom of said protrusion from the vertex being greater than that from the vertex to the end of said channel;   the axial distance between the point of engagement of said rod with said channel or point of catch of the connecting element held in the support, and the stop being smaller than the distance between the free end of the protrusion and the stop in the position of abutment of the protrusion against the stop;   the spring assembly being provided on its inner side with at least one indentation extending inwardly in deviation from a circular cross-section, and extending along at least part of the axial height of the spring assembly, and that the head being provided with milled grooves, corresponding to said at least one indentation.   
     
     
       2. An attachment means as claimed in claim 1, the at least one indentation being formed by an inwardly directed crimping provided in the outer wall of the spring assembly. 
     
     
       3. An attachment means as claimed in claim 1, the helical spring in an axial portion adjoining the head having an outer diameter which is smaller than, and preferably approximately equal to twice the distance of the indentation from the axis of the spring assembly. 
     
     
       4. An attachment means as claimed in claim 3, the said helical spring being provided with at least one turn resting against the bottom of the spring assembly, facing the base, having an outer diameter greater than the diameter of the helical spring in its axial portion adjoining the head, and preferably being approximately as wide as twice the radius of the non-indented inner side of the spring assembly; the indentation ending at an axial distance from the bottom which is at least as large as the axial thickness of the larger turn.   
     
     
       5. An attachment means as claimed in claim 1, the object being provided with an outside housing and an insulator, and on its rear side with a plate non-rotatably connected with the housing; the spring assembly being mounted non-rotatably on a surface of the plate on the side facing away from the base;   the plate being positioned inside the outer wall of the insulator, the rear surface of the plate facing the base being preferably flush with the rear rim of the outer wall; the outer wall being provided with at least one cam, projecting radially inward to interlock with a notch in the outer rim of the plate.